"In space," said the ad for "Alien" in 1979, "no one can hear you scream." In "Alien ," you don't have to bother about space. The third teaming of Sigourney Weaver and Ms. Slime is nothing to scream about. If there's suspense in the movie, it's in wondering why the title is a cubed sign, rather than "3" or "III" or just "Even More Aliens."

Never answered.

In terms of summer-movie oomph, something's missing. Perhaps the alien has become too familiar to us. "You've been in my life so long," Weaver tells her mucous opponent, "I can't remember anything else." Maybe it's the obvious lack of high-tech spaceware, or just the sense of sequel weariness. You know you're watching a rehash when the credits say "based on characters created by Dan O'Bannon and Ronald Shusett."

Once again, Weaver is shocked to discover the alien loose -- this time in a desolate prison colony. You'd think she'd get over those surprises by now. Once again, she has to rally a group of macho men (rapists and murderers) to take on the beast; and, once again, it doesn't take a college degree to guess who'll be left facing whom.

As Warrant Officer Ripley, she has been hypersleeping her way through space again, in that funny human pod box. She's also been dreaming about -- you guessed it. Her spaceship crash-lands on Fiorina 161, a barren planet used for a maximum-security correctional facility. For reasons that remain obscure, the prisoners have found a certain quasi-fundamentalist Christian faith, as bullied into them by jailbird mentor Charles S. ("Roc") Dutton.

Weaver suspects the indestructible alien may have been on board her ship. A burn mark here, an eviscerated dog there, you pick up on these things. When it becomes clear the creature is at large (after all, this is called "Alien "), Weaver assesses the available weaponry. On this colony, where supply ships are few and far between, there isn't much. She shaves her head (to get rid of the lice) and gets to work.

Ironically, "Alien " is not a bad movie. In fact -- here's the rub -- it's too interesting to make an exciting summer flick. At the core is a promising tale written by Australian filmmaker Vincent Ward, who made "The Navigator: An Odyssey Across Time," an often brilliant, time-hopping saga about medieval men journeying into the 20th century.

His "Alien " is woven out of the same classic sci-fi yarn. The prison is a Middle Ages-type institution, with gaunt-faced, monastic characters in robes walking through dark, twisting corridors bearing candles.

There are other small delights, more likely to have come from credited scriptwriters David Giler, Walter Hill and Larry Ferguson. Weaver strikes up a quickie affection with prison doctor Charles Dance -- an odd but appealing space-age wham-bam-thank-you-sir. There's a dramatically revealing conversation between Weaver and her half-destroyed robotic "droid," who recalls what happened on her ill-fated spaceship.

But most everything else feels like an excuse not to have more exciting (read expensive) things happen. This movie -- peopled with English performers, including Brian Glover, Ralph Brown, Paul McGann and Danny Webb -- seems more like a "Star Trek" episode than an "Alien" picture. It's also hard to get a handle on how big or small the alien is, the usual sign of low-budget horror filmmaking. Sometimes it seems small as a child; other times, it looms eight feet high. You begin to wonder if this is the real alien or just a stunt Muppet.